Long-term exposure to polystyrene microplastics reduces macrophages and affects the microbiota-gut-brain axis in mice

Mitigating microplastic-induced organ Damage: Mechanistic insights from the microplastic-macrophage axes

We live in a world increasingly dominated by plastic, leading to the generation of microplastic particles that pose significant global health concerns. Microplastics can enter the body via ingestion, inhalation, and direct contact, accumulating in various tissues and potentially causing harm. Despite this, the specific cellular mechanisms and signaling pathways involved remain poorly understood. Macrophages are essential in absorbing, distributing, and eliminating microplastics, playing a key role in the body's defense mechanisms. Recent evidence highlights oxidative stress signaling as a key pathway in microplastic-induced macrophage dysfunction. The accumulation of microplastics generates reactive oxygen species (ROS), disrupting normal macrophage functions and exacerbating inflammation and organ damage. This review serves as the first comprehensive examination of the interplay between microplastics, macrophages, and oxidative stress. It discusses how oxidative stress mediates macrophage responses to microplastics and explores the interactions with gut microbiota. Additionally, it reviews the organ damage resulting from alterations in macrophage function mediated by microplastics and offers a novel perspective on the defense, assessment, and treatment of microplastic-induced harm from the viewpoint of macrophages.

Chemical Food Safety in Europe Under the Spotlight: Principles, Regulatory Framework and Roadmap for Future Directions

Chemical food safety is a fundamental pillar of public health, regulatory governance, and economic stability, with far-reaching implications for human, animal, and environmental well-being. In the matter of chemicals in the food chain, the European Union (EU) has established one of the most sophisticated and robust regulatory frameworks to ensure food safety and balance consumer protection with scientific advancements and industry needs. This review provides a holistic analysis of the EU chemical food safety scenario, examining its regulatory framework, key risk assessment methodologies, and the roles of critical institutions involved in monitoring, enforcement, and policymaking. The new and evolving challenges of chemical food safety, including transparency, cumulative risk assessment, and emerging contaminants, were discussed. Special attention is given to major classes of chemical substances in food, their regulatory oversight, and the scientific principles guiding their assessment, as well as to the role of key actors, including regulatory agencies, official laboratories, and competent authorities. This work offers an updated and integrated analysis of chemical food safety in the EU, uniquely combining regulatory, scientific, and enforcement perspectives and providing a structured roadmap for future directions.

Association between microplastics exposure and depressive symptoms in college students

BACKGROUND

Microplastics (MP) are pervasive environmental pollutants that have raised concerns regarding their potential health effects. However, limited studies have investigated the relationship between MP exposure and depression, particularly in college students. Our study aims to examine the association between MP exposure and depressive symptoms in college students.

METHODS

A total of 1420 college students from Jiangsu College of Nursing, China, were included in this cross-sectional study. Depressive symptoms were assessed using the Patient Health Questionnaire-2 (PHQ-2), and MP exposure was estimated based on daily airborne MP concentration and drinking-water MP levels. Multivariate logistic regression models were used to estimate the associations between MP exposure and depressive symptoms.

RESULTS

The prevalence of depressive symptoms among college students was 61.8 %. The median (interquartile range) of total MP exposure was 17403.7 (14174.8-20995.9) particles/day. Airborne MP exposure exhibited positive associations with depressive symptoms, while no significant association was found between drinking-water MP exposure and depressive symptoms. Compared with participants in the lowest quartile of MP exposure, those in the highest quartile of total MP exposure had 38 % higher odds of experiencing depressive symptoms (odds ratio [OR] = 1.38, 95 % CI: 1.21-1.57). When treated as a continuous variable, each 1000-particle increase in total MP exposure was associated with a 7.0 % increase in the odds of depressive symptoms (OR = 1.07, 95 % CI: 1.04-1.10). Stratified analyses indicated that the association between MP exposure and depressive symptoms was stronger among male students and freshmen.

CONCLUSION

This study suggests MP exposure is a contributing factor for depressive symptoms in college students.

Microplastics in our diet: A growing concern for human health

Microplastics (MPs), particles smaller than 5 mm, are widely distributed in the environment, raising concerns about their long-term human health impact. MPs can enter the human food chain through various sources, including drinking water, salt, plant-based derived products, animal-based derived products (especially seafood), alcoholic beverages, and packaged food. Once in the human body, MPs have been detected in various biological tissues and secretions, such as feces, blood, semen, breastmilk, thrombi, colon, atheroma, and liver, highlighting their capacity for bioaccumulation. The most commonly identified polymers include polyethylene (PE), polypropylene (PP), and polystyrene (PS), along with others such as polyethylene terephthalate (PET), polyvinyl chloride (PVC), and polymethyl methacrylate (PMMA). This review presents a perspective on underexplored food contamination by MPs, discussing the presence of these plastic fragments in human biological systems and discussing in vivo studies that investigate their potential health risks. Emerging evidence links MPs to inflammatory responses, oxidative stress, and cellular dysfunction, potentially contributing to gastrointestinal disorders, neurotoxicity, reproductive toxicity, and cardiovascular risks. Key knowledge gaps persist for understanding health impacts under environmental relevant conditions, particularly regarding long-term exposure, particle size effects, chemical composition, and interactions with environmental pollutants. Addressing these challenges requires the development of advanced experimental models and human-relevant tissue studies, to improve understanding of MPs bioaccumulation, toxicity, and mechanisms of action. This work underscores the urgency of mitigating MP exposure and advancing studies to better understand their real implications for human health.

Biological Effects of Micro-/Nano-Plastics in Macrophages

The environmental impact of plastics is worsened by their inadequate end-of-life disposal, leading to the ubiquitous presence of micro- (MPs) and nanosized (NPs) plastic particles. MPs and NPs are thus widely present in water and air and inevitably enter the food chain, with inhalation and ingestion as the main exposure routes for humans. Many recent studies have demonstrated that MPs and NPs gain access to several body compartments, where they are taken up by cells, increase the production of reactive oxygen species, and lead to inflammatory changes. In most tissues, resident macrophages engage in the first approach to foreign materials, and this interaction largely affects the subsequent fate of the material and the possible pathological outcomes. On the other hand, macrophages are the main organizers and controllers of both inflammatory responses and tissue repair. Here, we aim to summarize the available information on the interaction of macrophages with MPs and NPs. Particular attention will be devoted to the consequences of this interaction on macrophage viability and functions, as well as to possible implications in pathology.

Chronic environmental exposure to polystyrene microplastics increases the risk of nonalcoholic fatty liver disease

Microplastics (MPs), as the crucial environmental pollutants, can be easily transported into the human body and accumulate in the liver. However, current studies mainly focus on acute exposure to MPs, investigations on long-term interactions with MPs alone remain limited. Thereby, we examined noxious properties of MPs and selected the most common polystyrene (PS) MPs as the research object, including unmodified PS MPs (PS-MPs) and positive-charged PS MPs (PS-NH2) at 10 mg/L employing oral drinking water methods in mice for six consecutive months in vivo. In vitro, we treated the human hepatocyte cells with MPs at 25 μg/mL to explore involved mechanisms. The results revealed that six-month MPs exposure led to nonalcoholic fatty liver disease (NAFLD) including impaired liver functions, extensive lipid depositions accompanied by abnormal levels of metabolic genes and PS-NH2 MPs exerted a stronger effect than PS-MPs. Concurrently, mice treated with MPs revealed the accumulation of senescent hepatocytes, leading to increased secretions of senescent phenotypes in the liver. We also discovered that MPs initiated the HO-1/Nrf2 axis consequently inducing ferroptosis in vivo and in vitro, as shown by massive iron deposition, extensive lipid peroxidation along with significant protein expressions in ferroptosis-related markers. Additionally, targeting the HO-1/Nrf2 pathway to further alleviate ferroptosis with corresponding inhibitors could efficiently alleviate cell senescence. Therefore, our study reveals new evidence of the relationship between chronic exposure to MPs and NAFLD and furthers the understanding of how plastic pollution affects human health.